Respirator with fluid amplifiers with fluid timer

ABSTRACT

An on-off inhalation valve of a respirator for admitting fluid to the lungs of a patient is controlled by a flip-flop fluid amplifier driven by a fluid amplifier during the exhalation cycle and by another fluid amplifier during the inhalation cycle and including a fluid timer for controlling the length of time of the pause between exhalation and inhalation.

[451 May 2,1972

United States Patent Peters et al.

......l37/8l.5 Metiuier.............................l28/l45 8 54]RESPIRATOR WITH FLUID 3,362,404 1/1968 AMPLIFIERS WITH FLUID TIMER3,429,324 2/1969 Brown et al.. [72] Inventors: Joseph C. Peters, EastHartford; Hermann 34462o7 5/1969 Ziermann, Cheshire, both of Conn.

General Medical Corporation June 17, I969 834,004

Primary Examiner-Dalton L. Truluck Assistant Examiner-G. F. Dunne [73]Assignee:

[22] Filed:

Attorney-Munson l-i. Lane and Munson H. Lane, Jr.

[57] ABSTRACT An on-off inhalation valve of a respirator for admittingfluid to the lungs of a patient is controlled by a flip-flop fluidamplifier driven by a fluid amplifier during the exhalation cycle and by[21] App]. No.:

another fluid amplifier during the inhalation cycle and including afluid timer for controlling the length of time of the pause betweenexhalation and inhalation.

8 Claims, 1 Drawing Figure Patented May 2, 1972 FIIL II NM RESPIRATORWITH FLUID AMPLIFIERS WITH FLUID TIMER BACKGROUND OF THE INVENTION Thisinvention relates to a respirator utilizing fluid amplifier logiccircuitry to control or assist respiration.

The above-mentioned patent application filed by Zierrnann and Petersdescribes and claims a fluid amplifier controlled respiration systemwhich utilizes a fluid amplifier to actuate a valve to open and closefor intermittingly communicating a source of fluid, such as air and/oroxygen, to the lungs of the patient. This patent application discloses arespirator that utilizes separate fluid amplifiers for accomplishing theswitching, namely, by providing an OR fluid amplifier for switching frominhalation to exhalation and an NOR fluid amplifier for switching fromexhalation to inhalation. It is sometimes desirable or necessary tocontrol the length of time of the pause between exhalation andinhalation and accordingly, this invention provides means coupled to oneof the sensing fluid amplifiers for governing these exhalationcharacteristics. What is meant by exhalation time is the time lapsebetween expulsion and inhalation or the period between breaths.

SUMMARY OF INVENTION A primary object of the present invention is toprovide an improved fluid amplifier driven respirator.

In accordance with the present invention a tim'mg means which controlsthe switching fluid amplifier is provided to control the length ofexhalation time of the breathing cycle.

Other features and advantages will be apparent from the specificationand claims and from the accompanying drawings which illustrate anembodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWING The sole FIGURE is a schematicillustration of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the soleFIGURE, the invention can best be understood by considering theinvention as being made up of three circuits: (1) the flow circuit forleading air and/or oxygen to the lungs of the patient and dischargingthe air expelled from the lungs of the patient, (2) the fluidic logiccircuitry for effectuating the switching from the inhalation andexhalation regimes of the breathing cycle, and (3) the timing circuitcontrolling the pause between exhaling and inhaling. As noted, airand/or oxygen from a source generally illustrated by reference numeralis supplied to the normally closed onoff inhalation valve 12 throughline 14. A suitable flow control valve generally illustrated byreference numeral 16 for adjusting the flow may be used if desired.During the inhalation cycle, fluid entering inhalation valve 12,previously actuated to the opened position, is ported to line 20 whereit is directed to the mouthpiece 22 for admittance to the lungs of thepatient. For a more detailed description of a suitable inhalation valvereference is hereby made to the commercially available valve identifiedas model 20l0 manufactured by Northeast Fluidics, Inc. bearing the tradename Fluidamp. It is customary to include a suitable ejector 24 whichserves to increase the volume of air delivered to the patient and sincethe ejector does not form a part of the invention, for the sake ofconvenience, the description thereof is omitted. Normally openedexhalation valve 26 previously actuated to its closed position i.e.closed to ambient) is disposed in line 20 between the ejector and thelungs of the patient. When in the exhalation cycle, inhalation valve 12is positioned to the ofl position and exhalation valve 26 isautomatically moved to the opened position for discharging the fluidexhumed from the lungs of the patient to ambient.

A nebulizer generally illustrated by numeral 29 may be utilized ifnecessary or desirable and is driven by the fluid evidenced in line 18upstream of the ejector 24. A suitable nebulizer may be of the typeshown in US. Pat. No. 3,379,194 granted to H. Ziermann on Apr. 23, 1968.It is noted that the nebulizer in this instance will only operate whenvalve 12 is in the on position. Thus, it only operates during theinhalation cycle and is inherently inoperative during the exhalationcycle, assuring that no medication is lost when the patient is exhaling.

Referring next to the logic circuitry which serves to sense certainparameters for switching the inhalation and exhalation valves in acertain timed relationship for defining the exhalation to inhalationratio. The logic circuitry can be considered as two systems, namely theone which comprises primary fluid amplifier generally illustrated bynumeral 30, exhalation control fluid amplifier 32, inhalation controlfluid amplifier 34, and the other for timing the pause betweenexhalation and inhalation which comprises fluid amplifier 33, backpressure switch 35, fluid amplifier 37 and the timing mechanismgenerally illustrated by reference numeral 82.

Preferably, fluid amplifier 30 is a flip-flop type where the flow fromthe power stream has no preference to either output channels andrequires some means such as pressure or flow at the control ports toefl'ectuate switching. Fluid amplifiers 32 and 34 are preferably of theOR and the NOR types, respectively. As is known, the OR and NOR types offluid amplifiers are the types where the power stream attaches to oneoutput channel and requires a positive signal for the OR and a negativesignal for the NOR to switch output channels.

Looking first at the three fluid amplifiers for controlling therespiration cycle, the power stream is connected to source 10 by supplyline 36 by way of branch lines 38, 40, 41 and 42. Stepdown resistors 25and 27 may be employed to lower the pressure where needed. Sincepressure from the source is typically 50 pounds per square inch gage(psig), the restrictor 25 reduces pressure to say 2 psig and restrictor27 reduces pressure to say 15 psig. These restrictors could be madevariable as is obvious to one skilled in the art and the scope of theinvention is not limited by the particular pressure reducing meansutilized. As it may be desirable to control the level of the switchingpressure, pressure control valve 43 preferably operating over a range of3 to 13 psig is disposed just upstream of branch lines 41 and 42.Sensing line 44 preferably connected to the mouthpiece of therespirator, although it may be located anywhere that is indicative oflung conditions, is connected to control port 46 of fluid amplifier 32and indirectly to control port 48 of fluid amplifier 34. As wasmentioned above, the fluid amplifier 34 is a NOR type and switches at anegative or near negative pressure signal. This is effectuated byconnecting a balloon type valve element 50 which opens and closesorifice 52. It has been found that this device increases sensitivityparticularly in the negative pressure regimes.

Looking at the operation of the logic circuitry, during the inhalationcycle when a small inspiration effort is made, the volume of air in line44 is reduced to a negative pressure. This loss in pressure deflatesvalve element 50, which normally closes off orifice 52, causing a lossof pressure in control port 48 increasing the pressure drop across thesplitter and hence diverting the output of fluid amplifier 34 fromoutput channel 54 to output channel 56. Since output channel 56 isconnected to control port 60 of the flip-flop fluid amplifier 30 by line58, the flow from the power nozzle in line 41 is diverted from theoutput channel 62 to output channel 64. This flow is then divided sothat a portion is admitted to valve 12 through line 68 for efi'ectuatingthe opening thereof and the other portion is admitted to exhalationvalve 26 by line 69 inflating balloon 75 seating it against seat 71 andpreventing escapement of air to ambient through bleed ports 73. Hence,fluid from the main supply line will flow unrestricted to themouthpiece.

Looking next at the exhalation cycle, when the patient is about toexhale, the pressure obviously has built up within the lungs which inturn is sensed and transmitted to the exhalation fluid amplifier 32through control port 46 causing the power stream to be diverted from theoutput channel to the output channel 72 where it is directed to thecontrol port 74 of the flip-flop amplifier 30 by way of line 76. Thiscauses the output stream in the output channel 64 to divert to channel62 so as to be transmitted to the timing logic circuitry. The loss ofpressure in lines 64 and 68 will permit the normally closed inhalationvalve 12 to close and the normally opened inhalation valve 26 to open;thus, the flow exhuming from the patients lungs will pass through theexhalation valve and dumped into ambient.

As was mentioned above, the timing mechanism serves to control thelength of time that it takes from the point of time the patientcompletes his exhalation to the time inhalation is repeated. Thus, thepause between breaths is determined by this timing mechanism. The signaltransmitted to output channel 62 in this embodiment is amplified by thefluid amplifier 30 which receives the constant power supply throughbranch line 72 connected to branch line 38 downstream of fixedrestrictor 25. Fluid amplifier 30 is a typical OR gate type and the flowfrom the power stream is normally attached to the output channel 76. Theadmittance of pressure into control port 78 serves to switch the powerstream to output channel 79 where it is in turn admitted to the controlport of fluid amplifier 37 by way of line 80. This serves to actuate thetiming mechanism generally indicated by numeral 82 by diverting thepower stream emanating from line 84 which is connected to line 36through fixed restriction 86 from the output channel 88 to the outputchannel 90. Fluid amplifier 37, like fluid am plifier 33, is an OR typewhere the power stream attaches to the output channel 88 and dumped toambient until the switching signal diverts the pressure stream to outputchannel 90. Line 92, connected to output channel 90 leads fluid into thetiming element 49. Timing element 49 consists of a cylindrical containerdefining a pair of chambers separated by wall 98, extending across theinner diameter and a cooperating diaphragm 94 also extending thereacrossand adapted to seal off orifice 96 formed in wall 98. Timing element 51is similarly constructed and consists of diaphragm 110 cooperating withorifice 112 formed in wall 111 extending thereacross. Variablerestrictor 100 is shunted across orifice 96 and interconnects the twovolume chambers 49 and 51, via lines 104 and 106. When pressure isadmitted into line 92, owing to the fact that there is less resistanceto enter timing element 49 than variable restrictor 100, it will firstenter the timing element 49. As soon as the pressure builds up behinddiaphragm 94, it will move downwardly against orifice 96. At this pointthe flow in line 92 will then be diverted through variable restrictor100 through line 106. The flow then will be admitted into timingelements 49 and 51 through line 108. When these elements are filled, thepressure acting on diaphragm 110 moves it against orifice 112 blockingoff line 118 connected to back pressure switch 35. The back pressureswitch 35 which is also a fluid amplifier, serves to switch the powerstream in line 114 from output channel 1 16 to output channel 124. Whenorifice 112 is not blocked off, the power stream normally passingthrough output channel 1 16 also permits flow to pass through controlport 119 through line 118, timing element 51, orifice 112 and bleed 113.Thus when orifice 112 is blocked ofi, a portion of the flow of backpressure switch 35 will enter passage 120 and through restrictor 122from line 114, causing a pressure differential across the splitter ofthe fluid amplifier and causing the power stream to divert to outputchannel 124. The power stream is then transmitted back to the flip-flopfluid amplifier 30 by way of line 126 and control port 127. This servesto switch the fluid and power stream 41 from channel 62 to channel 64for repeating the inhalation cycle. The length of time it takes for theswitch 30 to receive a signal will be determined by the volume ofchambers 130 and 140 in addition to the variable restriction 100 whichis adjustable to change the delay time.

It should be understood that the invention is not limited to theparticular embodiments shown and described herein, but that variouschanges and modifications may be made without departing from the spiritor scope of this novel concept as defined by the following claims.

We claim:

l. A fluidic controlled respirator for augmenting the breathing of apatient including a source of pressurized fluid to be injected into thelungs of the patient, a fluid line from said source to delivery meansadapted to admit fluid to the patient, an inspiration valve and anexpiration valve disposed in said fluid line and control means forsynchronously opening and closing said inspiration valve and expirationvalve for admitting fluid to and bleeding fluid from the patient, saidmeans including a pure fluidic amplifier responding to the condition ofthe lungs for intermittingly opening and closing said inspiration valveand said expiration valve, timing means for timing the delay betweenexhalation and inhalation, said timing means including a back pressurepure fluid amplifier switch, said switch having an output channelfluidly connected to a control port of said fluidic amplifier, and saidback pressure switch responding to a pressure signal generated by saidtiming means for efiectuating switching of said pure fluidic amplifierfor effectuating sequentially opening closing of said inhalation valveand said exhalation valve at a predetermined time interval.

2. A fluidic controlled respirator as claimed in claim 1 wherein saidtiming means includes a volume chamber and a restrictor, means forfluidly connecting said chamber and said restrictor in parallel relationso that fluid flows through said restrictor after said volume chamberfills, and said back pressure switch responsive to the condition whensaid fluid flows through said restrictor for actuating said controlmeans.

3. A fluidic controlled respirator as claimed in claim 2 including anadditional fluid amplifier having one of its output channels connectedto said volume chamber and said restrictor.

4. A fluidic controlled respirator having a source of fluid, a fluidline interconnecting said source and delivery means for filling thelungs of a patient, a normally closed valve for blocking off the flow ofthe fluid and a normally opened valve for interconnecting the lungs toambient disposed in said fluid line,

a. means for intermittently and synchronously opening said normallyclosed valve and closing said normally opened valve,

1. said means including a first fluid amplifier having an output channelfor directing actuating pressure to said normally closed and normallyopened valve for effectuating opening and closing thereof respectively,

2. a second fluid amplifier having an output channel connected to acontrol port of said first fluid amplifier,

3. a third fluid amplifier having an output channel connected to anothercontrol port of said first fluid amplifier,

4. means responsive to the breathing of said patient for controllingsaid second and third fluid amplifier whereby said first amplifierintermittently opens and closes said normally closed valve and saidnormally opened valve,

5. adjustable means for controlling the time delay between theexpiration and inhalation of the breathing cycle,

6. a pair of spaced volume chambers and a variable restrictor fluidlyshunting one of said volume chambers and discharging into said secondchamber, and

7. pressure responsive means responsive to when said volume chambersfill with fluid for actuating said first fluid amplifier.

5. A fluidic controlled respirator as claimed in claim 4 including afourth fluid amplifier having an output channel intermittently leadingfluid to said volume chambers and said variable restrictor.

6. A fluidic controlled respirator as claimed in claim 4 wherein saidpressure responsive means is a fluid amplifier and includes a controlport connected to one of said volume chambers and an output channelconnected to a control port of said first fluid amplifier.

7. A fluidic controlled respirator as claimed in claim 4 wherein saidvolume chamber includes a variable volume section and a flexible membercooperating with an orifice for closure thereof when the volume reachesa predetermined value.

8. A fluidic controlled respirator as claimed in claim 5 including afifth fluid amplifier having a control port connected to an outputchannel of said first fluid amplifier and an output 5 channel connectedto the control port of said fourth fluid amplifier.

1. A fluidic controlled respirator for augmenting the breathing of apatient including a source of pressurized fluid to be injected into thelungs of the patient, a fluid line from said source to delivery meansadapted to admit fluid to the patient, an inspiration valve and anexpiration valve disposed in said fluid line and control means forsynchronously opening and closing said inspiration valve and expirationvalve for admitting fluid to and bleeding fluid from the patient, saidmeans including a pure fluidic amplifier responding to the condition ofthe lungs for intermittingly opening and closing said inspiration valveand said expiration valve, timing means for timing the delay betweenexhalation and inhalation, said timing means including a back pressurepure fluid amplifier switch, said switch having an output channelfluidly connected to a control port of said fluidic amplifier, and saidback pressure switch responding to a pressure signal generated by saidtiming means for effectuating switching of said pure fluidic amplifierfor effectuating sequentially opening closing of said inhalation valveand said exhalation valve at a predetermined time interval.
 2. A fluidiccontrolled respirator as claimed in claim 1 wherein said timing meansincludes a volume chamber and a restrictor, means for fluidly connectingsaid chamber and said restrictor in parallel relation so that fluidflows through said restrictor after said volume chamber fills, and saidback pressure switch responsive to the condition when said fluid flowsthrough said restrictor for actuating said control means.
 2. a secondfluid amplifier having an output channel connected to a control port ofsaid first fluid amplifier,
 3. a third fluid amplifier having an outputchannel connected to another control port of said first fluid amplifier,3. A fluidic controlled respirator as claimed in claim 2 including anadditional fluid amplifier having one of its output channels connectedto said volume chamber and said restrictor.
 4. A fluidic controlledrespirator having a source of fluid, a fluid line interconnecting saidsource and delivery means for filling the lungs of a patient, a normallyclosed valve for blocking off the flow of the fluid and a normallyopened valve for interconnecting the lungs to ambient disposed in saidfluid line, a. means for intermittently and synchronously opening saidnormally closed valve and closing said normally opened valve,
 4. meansresponsive to the breathing of said patient for controlling said secondand third fluid amplifier whereby said first amplifier intermittentlyopens and closes said normally closed valve and said normally openedvalve,
 5. adjustable means for controlling the time delay between theexpiration and inhalation of the breathing cycle,
 5. A fluidiccontrolled respirator as claimed in claim 4 including a fourth fluidamplifier having an output channel intermittently leading fluid to saidvolume chambers and said variable restrictor.
 6. A fluidic controlledrespirator as claimed in claim 4 wherein said pressure responsive meansis a fluid amplifier and includes a control port connected to one ofsaid volume chambers and an output channel connected to a control portof said first fluid amplifier.
 6. a pair of spaced volume chambers and avariable restrictor fluidly shunting one of said volume chambers anddischarging into said second chamber, and
 7. pressure responsive meansresponsive to when said volume chambers fill with fluid for actuatingsaid first fluid amplifier.
 7. A fluidic controlled respirator asclaimed in claim 4 wherein said volume chamber includes a variablevolume section and a flexible member cooperating with an orifice forclosure thereof when the volume reaches a predetermined value.
 8. Afluidic controlled respirator as claimed in claim 5 including a fifthfluid amplifier having a control port connected to an output channel ofsaid first fluid amplifier and an output channel connected to thecontrol port of said fourth fluid amplifier.